The pathological isoform of the prion protein (PrPres) can serve as a marker for prion diseases, but more practical tests are needed for preclinical diagnosis and sensitive detection of many prion infections. During FY2012: 1) We trained and collaborated with human TSE surveillance groups to evaluate the utility of our previously developed RT-QuIC assay for the detection and diagnosis of human sporadic Creutzfeldt-Jakob disease. The data showed that RT-QuIC sensitively detects prion seeding activity in brain tissue from a wide variety of human CJD cases. Moreover, when applied to clinical cerebrospinal fluid samples, RT-QuIC has better sensitivity and specificity than any prior diagnostic cerebrospinal fluid test. 2) We determined how early after prion inoculation that we could detect signs of infection in the cerebrospinal fluid of hamsters using RT-QuIC. 3) Having previously detected prion infectivity in the nasal fluids of scrapie-infected hamsters, we determined the effects of disturbing the nasal mucosa on the release of prion infectivity. The results showed major increases in infectious prion release with a nasotoxic treatment.